GOING GREEN: David Ortiz speaks to Red Sox fans last Saturday, one day after one of the two Boston Marathon bombing suspects was caught. Tonight, the Celtics take center stage as the city recovers. Photo: Reuters; AP (inset); Getty Images (inset)

GOING GREEN: David Ortiz speaks to Red Sox fans last Saturday, one day after one of the two Boston Marathon bombing suspects was caught. Tonight, the Celtics take center stage as the city recovers. (Reuters; AP (inset); Getty Images (inset))

BOSTON — We remember, though we wish we didn’t have to. We share these experiences, these colliding emotions, even though, if we could, we’d purge them from our brains, our souls, our hearts.

We remember those awful weeks following Sept. 11, 2001, when friends and relatives and complete strangers would shake our hands and offer support and silent empathy for what had happened to our damaged city and our weary psyche.

We remember how we allowed sports to provide us with a salve, a couple hours a day, to make life seem normal again, to make the world seem less frightening again. In 2001 it was the Yankees, that fortress of relentless excellence, normally a lightning rod of disdain for the rest of the country, who provided the message, datelined “New York,” that we would go on. Maybe it didn’t turn the U.S. into a solid mass of Yankees fans. But nobody much complained when they won baseball games that autumn.

Tonight it is the Celtics, the basketball incarnation of those Yankees, with the 17 banners in the rafters, with the roster of legends that stretches back to the very start of the NBA. Tonight the C’s will host the Knicks for Game 3 of their opening round series, their first home game since the shrapnel pierced the hearts and emotions of this city on Patriots Day.

If you root for the Knicks, this isn’t going to make the mission tonight any less fervent for you. When the game starts, you will want to see the team in visiting blue take care of basketball business, try to seize a 3-0 lead in the series. But maybe you won’t be as rabid about it all as you might normally be. And maybe, if they lose, it won’t devastate you as it normally might.

We know, after all, how powerful these games can be.

We wish we hadn’t been there. But we were there.

“The mood around here is a mixed bag of emotions,” said Denise Chainey, an attorney whose offices on Dartmouth Street are only a few blocks away from where the bombs exploded. “There is a sense of resolve in the air. We’re moving on. Boylston Street opened [Wednesday] and the people came back, and the streets were busy.”

Yes. You remember the feeling.

And this one, too: “People I never met in my life … now I know their names as if they were my own.”

Even big cities become tiny hamlets when shared tears reduce their sheer size to a mere neighborhood with bigger buildings than most. We remember. We do. For a few seconds the other day, a handful of yahoos started booing Paul Pierce as he prepared a few remarks before Game 1 at Madison Square Garden, before they were ssssshushed into silence.

But we understood that, too. Back in those awful weeks almost 12 years ago, it took a while for people to recalibrate, to understand the Yankees weren’t the bad guys in the grand scheme of things, the “NY” on their hats and their chests represented something greater, and broader.

Same with Boston. Same with the Celtics.

It doesn’t mean the Knicks should sacrifice the night for any kind of greater good, and it doesn’t mean Knicks fans should feel guilty about wanting the Knicks to keep the Celtics down when they appear so vulnerable. I was at Game 7 of the ’01 World Series; Phoenix most assuredly did not ponder about how to react when Luis Gonzalez dunked the ball over Derek Jeter’s head. My ears still ring from the din.

And that’s part of it, too. In fact, it was a few moments after Scott Brosius had tied Game 5 of that series in the bottom of the ninth three days earlier that I got an e-mail from a friend from New Hampshire, the message simple: “Do you think I can hate the Yankees again with a clear conscience yet?”

All part of normalcy, in a decidedly un-normal time.

“I would never describe my husband, Wayne, as a fuzzy, emotional type,” Chainey said. “But there have been several times the last week and half that have choked him up to the point where he’s shed a tear a two. In my eyes that alone speaks volumes of the impact this attack has had on the city and its people.”